Class SpellChecker

Spell Checker class (Main class)
(initially inspired by the David Spencer code).

Example Usage (C#):

 SpellChecker spellchecker = new SpellChecker(spellIndexDirectory);
 // To index a field of a user index:
 spellchecker.IndexDictionary(new LuceneDictionary(my_lucene_reader, a_field));
 // To index a file containing words:
 spellchecker.IndexDictionary(new PlainTextDictionary(new FileInfo("myfile.txt")));
 string[] suggestions = spellchecker.SuggestSimilar("misspelt", 5);

Inheritance

System.Object

SpellChecker

Namespace: Lucene.Net.Search.Spell

Assembly: Lucene.Net.Suggest.dll

Syntax

public class SpellChecker : IDisposable

Constructors

SpellChecker(Store.Directory)

Use the given directory as a spell checker index with a LevensteinDistance as the default StringDistance. The directory is created if it doesn't exist yet.

Declaration

public SpellChecker(Store.Directory spellIndex)

Parameters

Type	Name	Description
Store.Directory	spellIndex	the spell index directory

SpellChecker(Store.Directory, IStringDistance)

Use the given directory as a spell checker index. The directory is created if it doesn't exist yet.

Declaration

public SpellChecker(Store.Directory spellIndex, IStringDistance sd)

Parameters

Type	Name	Description
Store.Directory	spellIndex	the spell index directory
IStringDistance	sd	the StringDistance measurement to use

SpellChecker(Store.Directory, IStringDistance, IComparer<SuggestWord>)

Use the given directory as a spell checker index with the given IStringDistance measure and the given for sorting the results.

Declaration

public SpellChecker(Store.Directory spellIndex, IStringDistance sd, IComparer<SuggestWord> comparer)

Parameters

Type	Name	Description
Store.Directory	spellIndex	The spelling index
IStringDistance	sd	The distance
IComparer<SuggestWord>	comparer	The comparer

Fields

DEFAULT_ACCURACY

The default minimum score to use, if not specified by setting Accuracy or overriding with SuggestSimilar(String, Int32, IndexReader, String, SuggestMode, Single) .

Declaration

public const float DEFAULT_ACCURACY = null

Field Value

Type	Description
System.Single

F_WORD

Field name for each word in the ngram index.

Declaration

public const string F_WORD = null

Field Value

Type	Description
System.String

Properties

Accuracy

Gets or sets the accuracy (minimum score) to be used, unless overridden in SuggestSimilar(String, Int32, IndexReader, String, SuggestMode, Single), to decide whether a suggestion is included or not. Sets the accuracy 0 < minScore < 1; default DEFAULT_ACCURACY

Declaration

public virtual float Accuracy { get; set; }

Property Value

Type	Description
System.Single

Comparer

Gets or sets the for the SuggestWordQueue.

Declaration

public virtual IComparer<SuggestWord> Comparer { get; set; }

Property Value

Type	Description
IComparer<SuggestWord>

StringDistance

Gets or sets the IStringDistance implementation for this SpellChecker instance.

Declaration

public virtual IStringDistance StringDistance { get; set; }

Property Value

Type	Description
IStringDistance

Methods

ClearIndex()

Removes all terms from the spell check index.

Declaration

public virtual void ClearIndex()

Dispose()

Dispose the underlying IndexSearcher used by this SpellChecker

Declaration

public void Dispose()

Exist(String)

Check whether the word exists in the index.

Declaration

public virtual bool Exist(string word)

Parameters

Type	Name	Description
System.String	word	word to check

Returns

Type	Description
System.Boolean	true if the word exists in the index

IndexDictionary(IDictionary, IndexWriterConfig, Boolean)

Indexes the data from the given IDictionary.

Declaration

public void IndexDictionary(IDictionary dict, IndexWriterConfig config, bool fullMerge)

Parameters

Type	Name	Description
IDictionary	dict	Dictionary to index
IndexWriterConfig	config	to use
System.Boolean	fullMerge	whether or not the spellcheck index should be fully merged

SetSpellIndex(Store.Directory)

Sets a different index as the spell checker index or re-open the existing index if

spellIndex

is the same value as given in the constructor.

Declaration

public virtual void SetSpellIndex(Store.Directory spellIndexDir)

Parameters

Type	Name	Description
Store.Directory	spellIndexDir	the spell directory to use

SuggestSimilar(String, Int32)

Suggest similar words.

As the Lucene similarity that is used to fetch the most relevant n-grammed terms is not the same as the edit distance strategy used to calculate the best matching spell-checked word from the hits that Lucene found, one usually has to retrieve a couple of numSug's in order to get the true best match.

I.e. if numSug == 1, don't count on that suggestion being the best one. Thus, you should set this value to at least 5 for a good suggestion.

Declaration

public virtual string[] SuggestSimilar(string word, int numSug)

Parameters

Type	Name	Description
System.String	word	the word you want a spell check done on
System.Int32	numSug	the number of suggested words

Returns

Type	Description
System.String[]	string[] the sorted list of the suggest words with these 2 criteria: first criteria: the edit distance, second criteria (only if restricted mode): the popularity of the suggest words in the field of the user index

See Also

SuggestSimilar(String, Int32, IndexReader, String, SuggestMode, Single)

SuggestSimilar(String, Int32, IndexReader, String, SuggestMode)

Calls SuggestSimilar(String, Int32, IndexReader, String, SuggestMode, Single) SuggestSimilar(word, numSug, ir, suggestMode, field, this.accuracy)

Declaration

public virtual string[] SuggestSimilar(string word, int numSug, IndexReader ir, string field, SuggestMode suggestMode)

Parameters

Type	Name	Description
System.String	word
System.Int32	numSug
IndexReader	ir
System.String	field
SuggestMode	suggestMode

Returns

Type	Description
System.String[]

SuggestSimilar(String, Int32, IndexReader, String, SuggestMode, Single)

Suggest similar words (optionally restricted to a field of an index).

As the Lucene similarity that is used to fetch the most relevant n-grammed terms is not the same as the edit distance strategy used to calculate the best matching spell-checked word from the hits that Lucene found, one usually has to retrieve a couple of numSug's in order to get the true best match.

I.e. if numSug == 1, don't count on that suggestion being the best one. Thus, you should set this value to at least 5 for a good suggestion.

Declaration

public virtual string[] SuggestSimilar(string word, int numSug, IndexReader ir, string field, SuggestMode suggestMode, float accuracy)

Parameters

Type	Name	Description
System.String	word	the word you want a spell check done on
System.Int32	numSug	the number of suggested words
IndexReader	ir	the indexReader of the user index (can be null see field param)
System.String	field	the field of the user index: if field is not null, the suggested words are restricted to the words present in this field.
SuggestMode	suggestMode	(NOTE: if indexReader==null and/or field==null, then this is overridden with SuggestMode.SUGGEST_ALWAYS)
System.Single	accuracy	The minimum score a suggestion must have in order to qualify for inclusion in the results

Returns

Type	Description
System.String[]	string[] the sorted list of the suggest words with these 2 criteria: first criteria: the edit distance, second criteria (only if restricted mode): the popularity of the suggest words in the field of the user index

SuggestSimilar(String, Int32, Single)

Suggest similar words.

As the Lucene similarity that is used to fetch the most relevant n-grammed terms is not the same as the edit distance strategy used to calculate the best matching spell-checked word from the hits that Lucene found, one usually has to retrieve a couple of numSug's in order to get the true best match.

I.e. if numSug == 1, don't count on that suggestion being the best one. Thus, you should set this value to at least 5 for a good suggestion.

Declaration

public virtual string[] SuggestSimilar(string word, int numSug, float accuracy)

Parameters

Type	Name	Description
System.String	word	the word you want a spell check done on
System.Int32	numSug	the number of suggested words
System.Single	accuracy	The minimum score a suggestion must have in order to qualify for inclusion in the results

Returns

Type	Description
System.String[]	string[] the sorted list of the suggest words with these 2 criteria: first criteria: the edit distance, second criteria (only if restricted mode): the popularity of the suggest words in the field of the user index

See Also

SuggestSimilar(String, Int32, IndexReader, String, SuggestMode, Single)